How to change struts

Resolved Question:

The purpose of a MacPherson strut, much like a shock absorber, is to dampen harsh spring movement and provide a means of dissipating the motion of the wheels. As a result, shocks encountered by the wheels are not totally transmitted to the body and, therefore, to you and your passengers. As the wheel moves up and down, the strut shortens and lengthens, thereby imposing a restraint on movement by its hydraulic action.

A good way to see if your struts are functioning correctly is to push one corner of the car until it is moving up and down for almost the full suspension travel, then release it and watch its recovery. If the car bounces slightly about one more time and comes to a rest, the strut is all right. If the car continues to bounce excessively, the struts will probably require replacement.

REMOVAL & INSTALLATION

See Figures 1, 2, 3, 4, 5, 6 and 7

Remove the top strut-to-body mounting nuts.

Loosen the wheel nuts, then raise and support the vehicle on jackstands. Make sure the weight of the vehicle is not on the control arm.

Fig. Fig. 2: Using a ratchet, remove the top strut-to-body mounting nuts

If equipped with a Tri-Pot joint, disconnect the drive axle from the transaxle before separating the strut from the steering knuckle.

If equipped, separate the ABS front brake sensor connection. These are on the 6000 STE models.

Before separating the strut from the steering knuckle, matchmark components by performing the following, as illustrated:

Using a sharp tool, scribe the knuckle along the lower outboard strut radius.

Scribe the strut flange on the inboard side, along the curve of the steering knuckle.

Using a chisel, mark the strut-to-steering knuckle interface.

Fig. Fig. 3: Before removal, make scribe marks on the knuckle along the lower outboard strut radius (view A), the strut flange on the inboard side, along the curve of the steering knuckle (view B), and across the strut-to-steering knuckle interface (view C)

Fig. Fig. 4: Use a chisel to mark the strut-to-steering knuckle interface

Remove the steering knuckle-to-strut bolts.

Fig. Fig. 5: With the use of two tools, remove the steering knuckle-to-strut bolts

The steering knuckle should be supported after removing the bolts to prevent axle joint overextension.

Remove the strut.

Fig. Fig. 6: After removing the bolts connecting the steering knuckle to the strut, the strut can be extracted from the vehicle

Install the strut to the body, then secure with the mounting nuts. Hand-tighten the nuts.

Place a jack under the lower arm. Raise the arm and install the lower strut-to-knuckle bolts. Align the strut-to-steering knuckle marks made during removal. Tighten the strut-to-knuckle bolts to 122-140 ft. lbs. (165-190 Nm), and the strut-to-body nuts to 16-18 ft. lbs. (22-24 Nm).

Reconnect the ABS sensor wiring.

Install the brake hose bracket to the strut.

Install the wheel, hand-tighten the lug nuts. Raise the vehicle slightly to allow removal of the jackstands.

If a new strut dampener has been installed, the front end will have to be realigned.

DISASSEMBLY & ASSEMBLY

See Figures 8 and 9

A MacPherson strut compressor tool J-34013-B or the equivalent must be used.

Mount the compressor tool J-34013-B in the holder J-3289-20.

Install the strut in the compressor J-34013-B, then install the compressor adapters, if used.

Compress the spring approximately 1 / 2 its height after initial contact with the top cap. Do not bottom the spring or the dampener rod .

Remove the nut from the strut dampener shaft and place the J-34013-27 on top of the dampener shaft. Using this alignment rod J-34013-27 guide the dampener shaft straight down through the bearing cap while decompressing the spring.

Fig. Fig. 8: Disassembly and assembly of the strut

Remove the components.

Assembly:

Install the bearing cap into J-34013-B if previously removed. Mount the strut into J-34013-B using the bottom locking pin only, then extend the dampener shaft and install J-34013-20 on the shaft.

Fig. Fig. 9: Special tools used by GM for suspension work

Install the spring over the dampener and swing the assembly up so that the locking pin can be installed. Install the upper insulator, shield, bumper, and upper spring seat. Make sure that the flat on the upper spring seat is facing in the proper direction. The spring should seat flat at 10° forward of the centerline of the strut assembly spindle.

Install tool J-34013-13 and turn, forcing the screw while J-34013-27 centers the assembly. When the threads on the dampener shaft are visible, remove tool J-34013-27, then install the nut.

Tighten the nut, using a crow's foot line wrench while holding the dampener shaft with a socket.

Remove tool J-34013-20.

REMOVAL & INSTALLATION

AWD Vehicles

See Figures 1, 2 and 3

The following tools or equivalent will be needed to do this repair: J-33432 leaf spring compressor and J-37619 ball joint stud remover.

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